Bistable relays



United States Patent ()iiice 2,895,027 Patented July 14, 1959 BISTABLE RELAYS Henry Ball, Burbank, Calif., assignor to Radio Corporation of America, a corporation of Delaware Application October 31, 1957, Serial No. 693,733 Claims. (Cl. 200-87) This invent-ion relates to electrical relays and particularly to a bistable electro-mechanical relay.

Bistable relays for performing electrical switching operations are known, the present invention being such a relay which is particularly simple and economical to manufacture. The relays are of the type whereby one electrical impulse to the relay coil will close an electrical circuit which will remain closed until the succeeding electrical impulse is impressed on the relay coil. Such relays have many uses, such as for controlling lights for large areas where the relays require low voltage and low current operation. They also may be used for low cost ofiice monitoring installations. In time-based program bus switching, a number of these relays may be used to eifect sequential control at selected intervals for activating projectors and changing slides. This simplifies the present switching operations on either an automatic time base or a manual stop-by-stop base. The relays may also be used in a master control switching system, as they do not require continuous energization of the control circuits. There is a use for them in remote control circuits of home radio and television receivers.

Simplicity of the relay has been obtained by the use of gravity to return an axially movable core or armature to normal rest position after every second electrical energization. However, non-gravity relays operating on the same principle may be desirable for certain uses. The armature or core is in two sections, one section of which closes and opens an electrical contact while the other section aids the first switch activating section during one energization of the relay coil.

The principal object of the invention, therefore, is to facilitate the operation of a bistable electro-mechanical relay.

Another object of the invention is to provide an improved electro-mechanical bistable relay.

A further object of the invention is to provide an improved bistable relay which has a minimum of moving parts, is positive in operation, and economical to manufacture.

A better understanding of this invention may be had from the following detailed description when read in connection with the accompanying drawings, in which:

Fig. l is a plan view of a relay embodying the invention.

Fig. 2 is a cross-sectional view of the relay taken along the line 2-2 of Fig. 1 and showing the relay core sections in one position.

Fig. 3 is a cross-sectional view similar to Fig. 2 and showing the core sections in a second position.

Fig. 4 is a cross-sectional view similar to Figs. 2 and 3 and showing the core sections in a third position; and

Fig. 5 is a cross-sectional view similar to the views in Figs. 2, 3, and 4 and showing the core sections in a fourth position.

Referring, now, to the drawings in which the same reference numerals identify the same elements, a tube 5 crimped at its lower end as shown at 6 is surrounded by a coil 7 connectable to a power source over conductors 8. Within the tube 5, which may be of brass, are two iron core sections 10 and 11.

Through a slot at the upper end of the tube 5 is the curved end of a switch contact leaf actuating spring 12 having a right angle portion 13 to which is attached an electrical contact element 14, the spring portion 13 being mounted in an insulating block 15 attached to coil 7 in any suitable manner. Parallel with the portion 13 of the spring 12 is a second switch contact spring 16 having a contact element 17 thereon which is positioned opposite the contact element 14.

To bring the contact elements '14 and 17 into contact, the coil 7 is energized over conductors 8, which will cause the two core sections 10 and 11 to be simultaneously moved upwardly to the position shown in Fig. 3 since the cores will over-shoot their central position shown in Fig. 5. This momentary over-travel movement of the core sections brings the ball portion 19 of section 10 past the curved end of the spring 12 and will move the spring portion 13 to the right to close the contacts 14 and 17. Upon de-energiza'tion of the coil 7, the lower core section 11 will drop to the lower end of the tube 5 by action of gravity. However, because of the position of the curved end of spring 12 under the ball 19, the core section 10 will be maintained in a position to maintain the contacts 14 and 17 closed. (See Fig. 4.) The rounded tip 20 prevents the core sections from adhering to one another.

Upon the second energization of the core 7, the two core sections 10 and 11 will be drawn toward the center of the coil 77 where they will collide (see Fig. 5) and both core sections will then drop to the lower end of the tube 5, as shown in Fig. 2. The removal of core section 10 from the spring 12 will open the contacts 14 and 17, as shown in Figs. 2 and 5. There is thus provided a bistable electro-mechanical relay which has a minimum of parts and is positive in its operation. For counting applications, a contact may be added at the bottom of the tube which when connected in series with the contacts 14 and 17 will result in a 2:1 divider.

As mentioned above, if a rotary relay is required or a horizontally positioned relay, a spring may be substituted for gravity.

I claim:

1. An electro-mechanical bistable relay comprising a coil, a tube within said coil and extending beyond both sides thereof, a pair of core sections within said tube, one position of said sections being in one end portion of said tube, and means extending into said tube at the other end thereof, energization of said coil being adapted to move said core sections into said coil until one end of one of said core sections contacts said means, said means holding said one core section in contact therewith and the other core section being adapted to return to the first-mentioned end of said tube upon de-energization of said coil.

2. An electro-mechanical bistable relay in accordance with claim 1 in which said means is a spring having a movable electrical contact thereon, a second fixed electrical contact being provided.

3. An electro-mechanical bistable relay in accordance with claim 1 in which a second energization of said coil brings both of said core sections into contact substantially at the center of said coil, said sections returning to the first-mentioned end of said tube upon de-energization of said coil.

4. An electro-mechanical bistable relay comprising a vertical tube, a pair of axially positioned and movable core sections in said tube, a coil surrounding the central portion of said tube, and means extending into one end portion of said tube, said means being adapted to hold 2,895,027 3 4 the upper section of said core sections when said upper References Cited in the file of this patent core section is brought in contact therewith.

5. An electromechanical bistable relay in accordance UNITED STATES PATENTS with claim 4 in which said means includes a spring hav- 9,212 Barry Mar. 20, 1923 ing an electrical contact thereon, said upper core section 5 ,658, 11 Blllynis Feb. 7, 1928 2,131,942 Evans et -al Oct. 4, 1938 moving said spring to close a circuit through said contact. 

